The present invention relates generally to an instrument arrangement for an automotive vehicle and, more particularly, to a lamp arrangement for irradiating an indicating portion thereof.
Various kinds of instrument arrangements for an automotive vehicle have been proposed in past years. One of such known instrument arrangements is disclosed, for example, in JP-A 58-172686.
This instrument arrangement has an indicating portion including characters, needles, etc. on which fluorescent materials are placed, and a so-called black light lamp as an excitation light source. When ultraviolet rays as emerged from the black light lamp fall on the characters, needles, etc. of the indicating portion, the fluorescent materials as placed thereon are excited to emit visible lights, resulting in an improvement of visibility of the indicating portion during driving in the dark or the night.
A problem encountered in the aforementioned instrument arrangement for an automotive vehicle is that since a mercury within the black light lamp has a freezing point not sufficiently low in temperature, intensity of radiation of the black light lamp decreases when the temperature in a cabin is not high, resulting in an insufficiency of brightness of the fluorescent materials placed on the characters, needles, etc. of the indicating portion.
Such problem may be solved by arranging an auxiliary light source for generating visible light in addition to the excitation light source.
Specifically, when intensity of radiation of the black light lamp decreases, the auxiliary light source is turned on to illuminate the indicating portion, thus preventing a decrease in visibility thereof. However, if the auxiliary light source is disposed in the instrument arrangement, there may arise another problem that the auxiliary light source, which is imaged in a front window of the vehicle, is in a driver's sight.
Referring to FIG. 6, visible light L of the auxiliary light source 103 as disposed in the instrument arrangement 101, which is reflected in the front window 105, reaches a passenger M.
In order to prevent a so-called front window reflection, a portion 109 of a hood 107 of the instrument arrangement 101 should be lengthened to the passenger M as indicated by a one-dot chain line in FIG. 6. This results in a restrained freedom of design for the instrument arrangement 101.